This invention relates generally to composite fabrics having unique aesthetic and physical characteristics. Specifically, the present invention relates to a textile composite that is comprised of a warp knitted, flame-resistant fabric and a flame-resistant extruded film, the two layers being heat laminated without the addition of any adhesives. The composite exhibits the characteristics of flame resistance and sound dissipation, making it particularly well-suited for application in a wide variety of vehicles, and especially well-suited for use as a vehicle headliner fabric.
In the manufacture of transportation vehicles, it is common practice to line the interior roof, as well as the interior sides and doors of the vehicle, with a suitable, aesthetically pleasing fabric. Ideally, such a fabric has the ability to dampen, or dissipate, sound, whether such sound is external to the vehicle (such as from traffic noises) or generated from within the vehicle (such as from engine noise).
As used herein, the word xe2x80x9cdissipatexe2x80x9d means to scatter, break up, or disperse. In relation to sound waves, dissipation refers to the act of deflecting sound waves in such a way as to minimize the sound. Dissipation can be achieved by reflecting the sound waves away from a surface or by allowing the sound waves to be transmitted through a surface, such as through the roof of a vehicle. In particularly noisy vehicles, such as large automobiles, trucks, buses, planes, trains, and the like, the dissipation of sound is particularly important to the comfort and well-being of the passengers.
Various materials and combinations have been utilized for the purpose of sound dissipation. Historically, a composite consisting of vinyl-coated foam was often used. This conventional vinyl-coated foam has several deficiencies, which include cost, limited design potential, poor sound absorption, and an inability to meet flammability testing requirements for use across a wide range of vehicles. As a result, it has become more common to use a textile material (such as a warp-knitted tricot fabric, for example) that is laminated to a foam base. Such textile-foam composites have improved design capabilities, but have limited durability due to the foam""s tendency to degrade. In addition, these composites do not address the flammability concerns of vehicle manufacturers.
It has been found that, in conventional headliner systems, the headliner fabric tends to separate from the foam either because the foam tends to degrade over time or because the adhesive between the foam and fabric tends to fail. This separation makes the fabric sag and droop, thus resulting in a condition that is both irritating and aesthetically displeasing to the vehicle occupants. An improved adherence between the headliner and the foam backing would represent a useful advancement over conventional headliner systems. Even more useful would be a liner that eliminates the foam component of the conventional headliner system, but that maintains a high degree of sound dissipation. The development of a sound-dissipating fabric for use in vehicles, which does not require the use of foam components, represents a useful advancement over conventional composites. The present invention represents such an advancement.
Textile composites are well known in the industry, as a means of adding strength or rigidity to a textile. In other applications, composite structures are comprised of aesthetically pleasing layers, which enhance the appearance of the final composite. The present invention embodies aesthetically pleasing layers that exhibit three sets of desirable characteristics; that is, the composite of the present invention is durable, is flame-resistant, and is capable of sound dissipation.
The present invention is a durable composite consisting of a polyester knitted fabric and an extruded film that are heat laminated together without the use of additional adhesive. The open-mesh structure of the fabric, when combined with the film, results in improved sound dissipation for the composite as compared with conventional textile headliners. Because both the fabric and the film components have flame retardant constituents, the resulting composite is capable of meeting even the most stringent of flammability requirements. An optional backing layer (made of foam or a suitable non-woven structure) may be added to the film layer to create a three-layer composite, which may be suitable for some applications.
Prior to inclusion in the composite, the knitted, open-mesh fabric can be dyed in a variety of colors to suit the tastes of vehicle manufacturers and their customers. Likewise, the extruded film that is laminated to the fabric is also available in many colors. The combinations of fabric color and film color lead to a variety of aesthetically pleasing composites. The color of the optional backing layer is not important, as that layer will not be visible to the vehicle occupants.
More important than appearance, however, is the requirement that, in the United States and in many other countries, any fabrics used in vehicles meet certain specific flammability standards. These standards are designed to protect vehicle occupants who may be involved in accidents, but these standards also disqualify many of the fabrics and fabric composites that might otherwise be used for their aesthetic appearance. The flammability tests required in the United States and Europe will be discussed herein.
The term xe2x80x9cflame resistantxe2x80x9d describes a material that bums slowly or is self-extinguishing after removal of an external source of ignition. A fabric can be flame resistant because of the innate properties of the fibers, the twist level of the yarn, the fabric construction, or, as in the case of the present invention, the presence of a flame retardant. The term xe2x80x9cflame retardantxe2x80x9d describes a class of chemicals which, when applied to a textile substrate during processing, help to reduce its flammability. A textile that has been treated with flame-retardant chemistry can be said to be xe2x80x9cflame retardedxe2x80x9d or xe2x80x9cflame resistant.xe2x80x9d
By producing a durable composite that meets these flammability standards and is also capable of dissipating sounds associated with vehicle travel, the present invention provides a useful advancement over the prior art.